How to Remove Tree Roots Under a Concrete Floor

Find out how to remove tree roots that are warping a concrete floor. Get tips on using a jackhammer to break up the affected section of the floor, then digging out the roots and repouring the concrete.

LESLIE: Rebecca in Alabama, you’ve got The Money Pit. How can we help you today?

REBECCA: We have a tree root that has grown into the foundation of our home. Did not realize it until we took the floor up. And we’ve got the tree down and the stump actually ground down so, obviously, the roots are still underneath the house. We have a lot of problems with the room that was damaged by the tree root, where it came – it has a big hump in the middle of the room. We’ve kind of covered it with furniture; it’s our media room. Used to be the garage of the house but it was enclosed when we bought it.

We have a lot of problems when it rains. Water, mud comes underneath the rug. And I was wondering if there is a way that we could somehow patch the floor or if we need to get someone to jackhammer up the cement floor that’s in here – because, again, it was the garage at one point, so it’s poured cement – or what we can do to kind of help the problem: if we have to repour the entire section, if we could dig up just that one section and maybe patch it up or what.

TOM: Well, first of all, there’s no reason you couldn’t cut out that one section and repour just that one section.

In terms of the water issue, I suspect what’s happening is the water is collecting somewhere outside of that area and it’s finding that the path of least resistance. So it’s pushing down around your foundation, under the floor and up into the garage. So you need to try to track down what that issue is. It’s probably a drainage issue somewhere outside those walls, either with gutters or downspouts or for some reason you’re getting too much water that’s collecting in that area. I would look to that as a source of the water.

But in terms of the floor, you can jackhammer it up in just a section and cut down – of course, remove all those tree roots. Because here’s the thing: now that the tree is dead, those roots will continue to rot away and you don’t want to have voids under that slab. Once the slab is up, you want to dig out as much of those roots as you can. And then you can put stone in there and repour that and cover it all up.

So those are the two things that I would do: I would remove the area where the bulge is, remove the tree roots and repour it. But also look to the source of the water, because I think that what’s happening is you’ve got a symptom there. The tree root is not causing the water to come in; it’s just following the path of least resistance and working its way in at that spot.